Power couple Naomi Watts and Liev Schreiber’s extensive downtown home hunt has ended with the purchase of a full-floor loft on Washington Street in TriBeCa.

The acting duo have closed on the 4,315-square-foot, three-bedroom, two-bathroom co-op for $3.95 million. The dramatic loft, which has 14-foot ceilings, oversized windows, river views and keyed elevator access, was listed for $4.5 million.

Watts and Schreiber have spent years examining the market. They scoped out units in Flatiron and West Chelsea in the past, and Watts recently checked out three West Village listings on her own.

The actress saw a $14.95 million townhouse at 38 Bethune St., a $6.5 million townhouse at 18 Jones St. and a $6.375 million townhouse at 36 Bedford St. before deciding to buy in TriBeCa instead.

Last week, Watts and Schreiber celebrated the birthday of her brother, photographer Ben Watts, at a party at Meatpacking District hot spot the Double Seven. Mick Jagger also attended the bash.

She’s so Lively

Forget the Upper East Side, “Gossip Girl” fans. Blake Lively was spotted, with a broker but without hunky beau Ryan Reynolds, visiting a $5.19 million penthouse at 140 W. 22nd St. The two-bedroom, 2 1/2-bathroom Chelsea duplex has 11-foot ceilings, a sky-lit media room and a rooftop that’s ideal for entertaining. The wraparound rooftop terrace includes a kitchen, a plasma TV and reinforced steel beams that allow it to accommodate more than 100 people.

We covered this penthouse when it hit the market in November, for a slightly higher price of $5.4 million. It belongs to Bill White and Bryan Eure, who had the first gay wedding at the Four Seasons — a high-profile event where Aretha Franklin sang in front of guests including Gayle King and Karolina Kurkova. White is the former president of the Intrepid Sea, Air & Space Museum and current CEO of Constellations Group, and Eure is an insurance executive with Willis Group Holdings.

Corcoran Group listing broker Meris Blumstein declined to comment.

Lively seems focused on finding a swanky downtown home. As previously reported, Lively and Reynolds looked at a $4.35 million penthouse at 225 Fifth Ave. and a $12.85 million penthouse at 130 W. 12th St.

Sightings

Ricky Martinplaying with his twins in the playroom at the Upper East Side’s Lucida building . . . Prudential Douglas Elliman brokers Melanie Lazenby and Dina Lewis pitching a listing six days after Lewis gave birth to daughter Hannah Morgan Lewis.

First serve

Caroline Wozniacki isn’t just a top-ranked tennis player. She’s also a real-estate investor.

The Danish star plunked down almost $9 million for a pair of two-bedroom condos at 15 Union Square West. And now one of them is on the market for rent, for $17,500 a month. We’re told that Wozniacki bought both units as investments.

The fourth-floor, two-bedroom, 2 1/2-bathroom duplex that Wozniacki wants to rent out is 2,282 square feet. It has 16-foot ceilings, floor-to-ceiling windows, an open chef’s kitchen and a master bathroom with a claw-foot soaking tub. The unit is available furnished or unfurnished.

The building, where Facebook/PayPal billionaire Peter Thiel also has a unit, features a lap pool, hot tub and sauna.

Corcoran Group listing broker Meris Blumstein declined to comment.

Thierry nice

How quietly is famed fashion designer Thierry Mugler shopping around his penthouse duplex? The $7.995 million apartment is so hush-hush that the listing doesn’t even mention the address, which we can reveal is 245 Seventh Ave.

Not surprisingly, the 4,100-square-foot condo “perched atop a prime Chelsea prewar building,” looks gorgeous. It has two bedrooms, 2 1/2 bathrooms and impressive city views, especially from its 800-square-foot private, landscaped roof deck.

The duplex has a dramatic floating staircase that leads up to a conservatory with a big skylight and floor-to-ceiling windows.

We hear . . .

That James Lafferty of “One Tree Hill” is the latest TV star to move into the Edge condo development in Williamsburg. Ed Westwick of “Gossip Girl” also has a unit at the Edge . . . That chef Masatoshi Sugio, owner of the Sushi of Gari restaurants, just closed on a one-bedroom condo at 515 E. 72nd St. Fellow chef Eric Ripert is also in the building.